Decorative Christmas tree



FIG. 1 is a front, perspective view of a decorative Christmas tree showing my new design;

FIG. 2 is a rear, perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a rear view thereof; and,

FIG. 8 is a bottom plan view thereof.

The broken lines shown around the tree is included for purposes of environment and forming no part of the claimed design. 

The ornamental design for a decorative Christmas tree, as shown and described. 